Why do you think it's okay to confiscate people's property?
Even if a particular item isn't allowed on carry-on, why is it just assumed to be acceptable to permanently steal it from the passengers unless their was a suspicious of malice and it was evidence in the criminal case against them?
This is particularly true of the cannon and chainsaw. Unless the cannon had gunpowder and the chainsaw fuel, both are useless as weapons. (At best really clumsy bludgeons.) Even if you decide to not allow them in carry-on, because... {handwave} reasons... why is it necessary to permanently steal it from the passenger to use as a trophy, rather than put it in the baggage hold or allow the owners to make arrangements to reclaim their property later? (Hell, it's an airport, there's going to be a freight company like FedEx nearby. Given the number of items being taken from passengers, returning them seems a pretty simple thing to standardise.)
But look it another way, this is the cream of the crop, gathered from nationwide, the trophies the TSA puts on show to justify their existence and try to deflect criticism. And yet most of the items seem to many of us to be hysterical overreactions, that few of the items should have actually been confiscated from the passengers, and even fewer permanently.
So if that's the best of the best, how bad is the rest of the haul?